FIELD OF THE INVENTION
The invention concerns a double-closure valve.
We have created a valve comprising a body including a chamber communicating with two lateral conduits. Two superposed closures are mobile in said chamber along a common axis perpendicular to the two lateral conduits. The lower part of the chamber includes a first seat for the top closure and a second seat for the bottom closure below the first seat.
The valve body incorporates a second chamber under the aforementioned two seats and into which a third conduit discharges. The closures are each carried by a swing mobile between a position in which the closure bears in a sealed manner on the corresponding seat and a position in which the closure is spaced from said seat. The swing of the bottom closure incorporates an internal passage that discharges into a space between the two closures.
The two closures can be moved independently of each other, each with its own range of movement, to clean the valve.
The internal passage in the swing of the bottom closure enables the cleaning liquid to be drained off to a collector.
The above valve has the following drawback:
When the two closures are in the closed position bearing on their seat, there is a space between the two seats that communicates with the passage in the swing of the bottom closure.
This space disappears when the closures are open. However, for a very short time period before the closures reach their fully open position the space between the two closures is in communication with the aforementioned passage.
As a result the liquid passing through the valve can leak via the above passage.
The aim of the present invention is to remedy the above drawback by fitting the valve with means for preventing liquid leaking via the aforementioned passage when the closures move from their closed position toward their open position.